''It was a good start to my round,'' Kim said. ''I had a good up-and-down on the first as well for par, so got myself on a good roll.''

On the 17th, she holed a 20-foot putt from the fringe.

''Just got a really good roll on the ball,'' Kim said. ''And for the first time in probably five months, I've gotten excited. So I was like, ''Come on, come on!'' And it fell on the last rotation, so I was pretty pleased with that.''

Kim also birdied Nos. 4, 7 and 16 in her bogey-free round. She won the last of her two LPGA Tour titles in 2005.

Spain's Azahara Munoz was second. She eagled No. 17 to tie for the lead and dropped back with a bogey on the par-4 18th.

''I played so well today. I made a lot of good putts. I actually should have made a lot more, so that was nice.''

Third-ranked Lydia Ko birdied the final two holes for a 68. The 17-year-old New Zealander has two victories this year.

Lizette Salas, Gerina Piller and Pornanong Phatlum shot 69. Top-ranked Inbee Park and Lexi Thompson, the winner last year at Guadalajara Country Club, were in the group at 70.

Salas overcame an opening double bogey

''I think I was a little bit nervous at the beginning,'' Salas said. ''Just kind of playing in Mexico, where my parents are from.''

Her father, Ramon, made the trip with her from California.

''He hasn't been out for a long time,'' Salas said. ''Coming back to Mexico has been special for him. His family, our family, is about six hours from here. ... It's funny, they thought I didn't speak Spanish and I said, `Of course, I do!' I'm almost fluent.''

Michelle Wie bogeyed three of the first seven holes in a 73. She won the 2009 event for her first LPGA Tour victory.

Second-ranked Stacy Lewis had a 76, leaving her tied for 31st in the 36-player field.